Generate wxEVT_SEARCHCTRL_SEARCH_BTN when Enter is pressed

Make it possible to bind to just wxEVT_SEARCHCTRL_SEARCH_BTN under all
platforms: previously, it was also necessary to bind to wxEVT_TEXT_ENTER
when using the generic implementation, as pressing Enter in the text
control didn't generate the dedicated SEARCH event.

It does now, and, to avoid any confusion, the control does not generate
wxEVT_TEXT_ENTER events at all any more. This is not really
incompatible, as wxOSX never generated these events anyhow and the
generic version only did for a couple of days, since the changes of
9816970797 which were, finally, misguided
and so are undone by this commit.

Closes #17911.

interface/wx/srchctrl.h

@@ -12,10 +12,6 @@
     control, and a cancel button.
 
     @beginStyleTable
-    @style{wxTE_PROCESS_ENTER}
-           The control will generate the event @c wxEVT_TEXT_ENTER
-           (otherwise pressing Enter key is either processed internally by the
-           control or used for navigation between dialog controls).
     @style{wxTE_PROCESS_TAB}
            The control will receive @c wxEVT_CHAR events for TAB pressed -
            normally, TAB is used for passing to the next control in a dialog
@@ -39,8 +35,11 @@
     @endStyleTable
 
     @beginEventEmissionTable{wxCommandEvent}
-    To retrieve actual search queries, use EVT_TEXT and EVT_TEXT_ENTER events,
-    just as you would with wxTextCtrl.
+    To react to the changes in the control contents, use EVT_TEXT event, just
+    as you would do with wxTextCtrl. However it is recommended to use
+    EVT_SEARCHCTRL_SEARCH_BTN to actually start searching to avoid doing it too
+    soon, while the user is still typing (note that EVT_SEARCHCTRL_SEARCH_BTN
+    is also triggered by pressing Enter in the control).
     @event{EVT_SEARCHCTRL_SEARCH_BTN(id, func)}
         Respond to a @c wxEVT_SEARCHCTRL_SEARCH_BTN event, generated when the
         search button is clicked. Note that this does not initiate a search on
@@ -56,7 +55,7 @@
     @category{ctrl}
     @appearance{searchctrl}
 
-    @see wxTextCtrl::Create, wxValidator
+    @see wxTextCtrl
 */
 class wxSearchCtrl : public wxTextCtrl
 {